andrews



(No Model.) 2 Sheets-Sheet 1.

J. D. I'. ANDREWS.

ELEGTRIG'ARG LAMP.

Patented Oct. 24, 188.2.

`By his Jlurneys @uw ,Maw

N. ruins, Pham-Lummen.. wnmnim. u. o

(No Model.) 2 Sheets-Sheet 2 J. D. F. ANDREWS.

ELEGTRIG ARG LAMP.

10.266,337. Patented 00h24, 1882..

' Jammu/for.'

UNITED STATES PATENT OFFICE.

JOSEPH D. F. ANDREWS, OF CHARLTON, COUNTY OF KENT, ENGLAND.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 266,337', dated October 24, 1882.

Application filed August 25, 1881. (No model.) Patented in England Juno 1l, 1879, No. 2,321, and in France December 10, 1879,

To all whom it may concern:

Beit known that I, JOSEPH DAVENPORT FINNET ANDREWS, of Charlton, in the county of Kent, England, a subject of the Queen of Great Britain, have invented certain new and useful Improvements in Electric-Arc Lamps, of which the following is a specitication.

In the accompanying drawings, Figure 1 is an end or edge view, and Fig. 2 a side or front view, of my improved lamp, showing the automatic lighter ;r Fig. 3, a sectional detail view of the coil and split core of my automatic lighter. Fig. 4 is an end view of a lnoditication in which the automatic-lighter-operating devices are applied to actuate one of the electrodes of the lamp to automatically light it, and Fig. 5 is a front view of the same. Fig. 6 is a perspective'view of two carbon plates of different lengths, showing` the manner of connecting them in circuit; and FiO. 7 is a perspective view of a carbon-plate electrode.

The first part ot' my invention relates to the electrodes of the lamp. I employ two plates or disks ot' carbon, which constitute the electrodes. They are placed parallel face to face a short distance apart', either with or without an insulating material or with or without an insulated carbon plate or disk between them. The electrodes being connected in electric cir cuit, the luminous are presents itself at some point on their edges and slowly travels back and forth, burning them and the insulating material or insulated carbon plate or disk between them. This feature of my invention is illustrated in Figs. l and 2, where a a are carbon-plate electrodes placed face to face and mounted in the jaws b b of an electric lamp. b is. the insulated carbon plate, which may or may not, as above mentioned, be placed between the electrodes. Then the circuit is completed by suitable means at some point t' between the electrodes it will be consumed as the electrodes are burned. As above indicated, the electrodes may be burned with nothing between them. By this arrangement the inner side of each electrode is protected from the atmosphere and the outside exposed. The edges therefore always retain the chisel or beveled shape shown in the drawings, and consequently the arc is comparatively short and emits but little violet light. This is also true where even very thick plates are used. The electrodes, being ot' such broad dimensions, have a very low resistance and will burn for a great length of time.

Where the lamp is to be worked with an alternating current the carbon plates maybe of equal thickness; but when the current is constant the positive plate is made thicker than the .other to allow for its more rapid consumption.

lhen the light is required to be evenly dit'- fused in all directions I make both plates ot' the samelength; but when the illumination is required principally in one direction one ot' the plates-preferably that forming the positive poleis made longer than the other, and in this case, in order to prevent the arc from traveling about on the face of the longer plate, it is found advantageous to make the connection with the plates at opposite ends, thus causing the are to remain at the edge ol" the carbon. This last feature is illustrated in Fig. G, where the wires .t and y are shown as connected at opposite ends of the two plates.

In order to secure a greater steadiness of light, I construct the plateelectrodes of a number of layers of carbon of different densities and form. Usually I take two layers--one of plumbago or charcoal made slightly impure by the introduction of a small quantityot' magnesia, slate, or clay, and the other a pure carbon made from ground coke in the usual way. This is illustrated in Fig. 7, where a carbonplate electrode, A, is shown, consisting of two layers, n m, ot' diiferentdensities.

In constructing the lamps to burn in parallel circuit I usually make both the carbon plates fixed and light them, or complete the circuit between the carbons by an electro-inagnetic lighter in circuit with the lamps and IOO automatically operated by the current that supplies the lamps. rlhis automatic electric lighter constitutes the second part ot' my invention, and is illustrated in Figs. 1,2, and 3. It consists of an electro-magnet in circuitwith the carbons of the electric lamp, the core of which magnet is split into two or more longitudinal sections, d e, one of which is pivoted to the frame of the lamp, and has attached to its prolonged arm a piece of some conducting material, which it causes to bear on the edge of each electrode when no current is passing through the circuit. The other sections are trmly attached to the frame of the lamp.

On passing a current through the helix of the magnet the circuit between the lamp-electrodes is completed through the conductor resting against their edges; but at the saine time the core is magnetized the split sections repel each other, the carbon-lighter is thrown out of contact with the carbon-electrodes, and the lamp is lighted. In this position it will be held until the current ceases to flow through the helix, when the core will be demagnetized, the sections fall together, and the lighter be again caused to close the circuit between the electrodes ot' the lamp. To complete the circuit I use a small piece of carbon or other material conducting well and offering a resistance equal, or nearly so, to the arc.

Referring to the drawings, c is the coil or helix of an electro-magnet, having one terminal, c', connected to carbon plate a.

d c are sections of the split core. Section c is firmly attached to the bobbin of the coil c and section d to one arm of the iron lever df, which is pivoted at j'.

g is a piece of carbon secured to the upper end of lever d by a clamp or other suitable means. The armature of section d consists of an iron strip, 7L, which trmly secures coil c to the base of the lamp.

The operation is as follows: When no current passes through the lamp sections d and e of coil c are demagnetized and rest against each other. This brings carbon g in contact with the edges of each of the carbon plates a a at fi, and a closed circuit is established through coil c and between the electrodes a u. On passing a current through this closed circuit sections cl c of coil c become similarly magnetized. Section d is repelled by fixed section e and attracted by armature h, toward which it moves, throwing carbon g out of contact with the edges ot' the electrodes a a. The circuit having previously been completed across the edges of the electrodes, the voltaic arc presents itself at t' as soon as the carbon g is removed and the lamp is lighted. The voltaic are now travels slowly up the plates to the top, where itmoves about, burning theplates away evenly. rlhe sides ot' the plates are cut awayobliquely to prevent the too quick ascension of the arc to the top, which is liable to cause extinguishment.

As long as the arc is maintained across the plates 'and the circuit is uninterrupted the lighter is held away from the electrodes by the mutuallyrepulsive action of sections d and e and the attraction ot' armature h but as soon as the arc fails or the circuit is in any wise broken sections d and c fall together, carbon g returns by gravity to its position in contact with the edges ofthe electrodes, and the lamp is ready for relighting. It is obvious that it' the circuit is broken only by the failure otl the arc across the electrodes the lamp thus automatically relights itself.

In Figs. 4 and 5 I have illustrated a modification of this part of my invention, in which the carbon-lighter g is dispensed with and the carbon-holder ot' electrode ct is clamped to lever d of section d of the split core ot' the magnet. rIlhe other parts are in all respects similar to those shown in Figs. l and 2. Then no current is passing through the line sections d and c repose against each other and carbon a is in contact with carbon a, closing the electric circuit through coil c and electrodes ct and a. 0n passing a current through the circuit sections cl and c are magnetized, section d is repulsed by c and attracted by armature 71, to which it moves, electrode d is moved ont ofcontact with a., and the electric arc established between them. On the cessation of the current the circuit between the carbons is closed in a way similar to that already described, ready for the relighting of the lamp. K is a set-screw, having a coiled spring, 7.", againstit, which limits the motion of electrode a' and determines its distance from the other electrode and the length of the arc.

rlhe right to apply for a patent upon the electro-magnetpci1 se herein shown and described is reserved, in order that, it' it is deemed necessary and expedient for the protection ot' the invention, another application may be hereafter filed.

That I claim as my'invention is 1. In an electric lamp, bread plate-electrodes placed parallel face to face, substantially as set forth.

2. In an electric lamp, the plate-electrodes placed parallel face to face, one heilig' shorter than the other, substantially as and for the purpose set forth.

3. The plate-electrodes consisting ot' layers of carbon differing in purity, substantially as set forth.

t. The electric lighter, substantially as herein described, which consists in the combina.- tion of the helix, its split core, the pivoted lever, and the carbon attached thereto.

5. The combination, substantially as herein described7 of the helix, its split core, the pivoted lever, the carbon attached thereto, the iron strip or armature, and electrodes of an electric lamp.

t3. The combination, substantially as herein described, of the helix, its split core, the pivoted lever, the carbon attached thereto, and electrodes or" an electric lamp.

IOO

IIO

7. The combination of the plate-electrodes scribed my name this 20th (lny of J une, A. D. placed parallel face to face, the carbon-lighter 1881. g, which establishes the arc at the sides of the T ,T plate-electrodes below their upper edges7 and J' D F' ALNDRE" b 5 the electro-magnet and the mechanism for Witnesses:

operating the lighter, substantially as set forth. HoRA'rIo DMN,

In testimony whereof I have hereunto sub- WM. H. W. JEFFERIES. 

